In modern semiconductor memory modules, a plurality of semiconductor memory chips, for example Dynamic Random Access Memories (DRAMs), are mounted on an electronic printed circuit board, which semiconductor memory chips can be operated in parallel and can simultaneously receive electrical signals. In this case, the electronic printed circuit board serves for distributing the electronic signals and may itself be connected to a superordinate electronic unit via a contact strip provided with contact terminals. To distribute the electronic signals and to read out data, the printed circuit board is provided with conductor tracks which may run in a plurality of planes within the printed circuit board.
Due to the rising demand for memory performance, it is desired to mount an increasing number of semiconductor memory chips on an individual semiconductor memory module without increasing the area of the module or of the electronic printed circuit board in the process. Moreover, the line tracks are desired to be as short as possible to keep the signal propagation times as short as possible.
Semiconductor memory modules are typically equipped such that the semiconductor memory chips are arranged symmetrically with respect to the center of the semiconductor memory module. By way of example, between the center and an edge of the semiconductor memory module that runs perpendicularly to the contact strip, at least eight semiconductor memory chips of identical type are mounted next to one another in two rows. In this case, only eight of the semiconductor memory chips serve for storing data, while one semiconductor memory chip serves as an error correction memory chip which compares the signals of the other eight semiconductor memory chips to avoid errors during storage and read-out.
Modern semiconductor memory chips have a square or rectangular form. It generally holds true that the dimensions of the semiconductor memory chips scale with the storage capacity. In particular, modern semiconductor memory chips with a particularly large storage capacity have comparatively large dimensions.
The problem arises that the electronic printed circuit boards for semiconductor memory modules in industrial series production have a standard size, in the case of rectangular memory chips with a large storage capacity, e.g., DDR3-DRAM memory chips, can no longer be arranged in two rows, lying one above another.
Moreover, when arranging the memory chips, care must be taken to ensure that an arrangement is found which exhibits the occurrence of signal propagation times that are as uniform as possible to all of the semiconductor memory chips in conjunction with conductor track lengths that are, to the greatest extent possible, identical in length. Meanwhile, the conductor track lengths are also desired to be as short as possible to keep the signal propagation times as short as possible.
Accordingly, it would be desirable to have a semiconductor memory module that can be equipped with comparatively large rectangular semiconductor memory chips, e.g., DDR3-DRAM memory chips, in two rows lying one above another, with the conductor tracks to the respective semiconductor memory chips being identical in length and as short as possible.